SPENCER (AP) – Marathon County officials say an estimated 1 million gallons of manure have spilled from a farm storage tank into wetland and the Little Eau Pleine River.

A county conservation official tells Wausau Daily Herald Media Wednesday the discharge from the 120-cow Willcome dairy farm lasted for about a year.

A Wisconsin Department of Natural Resources water specialist says the state estimates 600,000 gallons leaked from September to May. The specialist says the farm’s two manure spreaders broke and the farmers were receptive to state requests.

Farm owner Patrick Willcome pleaded no contest Aug. 1 to violating water pollution regulations. He was found guilty and fined $460. He didn’t return calls Tuesday from Daily Herald Media.

Officials learned of the spill May 2 in an anonymous letter to the DNR.